On FIGS. 1 and 2 is shown an electrochemical measurement arrangement such as described in the patent application FR 92 01331.
On FIG. 1 is shown partially and in perspective an exploded view of the multiple zone sensor including an insulating substrate 2 on the surface of which are provided two electrodes 4 and 6 serving to conduct an electrical measurement current. On such electrodes 4 and 6 is provided a coating 8 also insulating.
The coating 8 includes a first series of openings 10a, 10b, 10c at least partially superposed onto the first electrode 4 and a second series of openings 12a, 12b, 12c at least partially superposed onto the second electrode 6. At one end 13 of coating 8 is provided at least one opening 14 serving to free an electrical contact surface on each of the two electrodes 4 and 6.
It will be noted that electrodes 4 and 6 are electrically insulated from one another and that the first series of openings 10a, 10b, 10c is not superposed onto the second electrode 6. Likewise, the second series of openings 12a, 12b, 12c is not superposed onto the first electrode 4. Each pair of corresponding openings respectively 10a and 12a, 10b and 12b, 10c and 12c, defines an active zone of the multiple zone sensor.
The electrochemical functioning of such a multiple zone sensor is substantially identical to that of a single zone sensor such as described for example in the patent application Wo 92/14836.
The substance to be analyzed, for example blood in a possible application for the measurement of glucose therein, is brought into one of the active zones of the multiple zone sensor. To effect a valid electrochemical measurement it is necessary that only one of the active zones of the multiple zone sensor be covered by the substance to be analyzed, the remaining active zones having necessarily to remain unused.
On FIG. 2 is shown an electrochemical measurement arrangement designated by the general reference 20 intended to receive a removable multiple zone sensor of the type of that described on FIG. 1.
The electrochemical measurement arrangement 20 comprises a case 22 in the interior of which is provided electronic measurement means 24. Additionally, such electrochemical measurement arrangement 20 comprises an advancing arrangement 26 serving to displace the multiple zone sensor 28 introduced into the interior of case 22.
In order to cut off an active zone, following use thereof in order to effect an electrochemical measurement, of the multiple zone sensor 28 so as to separate the portion of such multiple zone sensor 28, including such used active zone, from the remainder of the latter, there is provided a cutting arrangement 30.
The cutting arrangement 30 comprises a push-piece 32 and a blade 34 fixed to such push-piece 32. The cutting arrangement 30 is arranged in a manner such that push-piece 32 is adapted to effect a displacement, in a direction transversal to the multiple zone sensor 28, sufficiently great to permit blade 34 to traverse completely such multiple zone sensor 28.
The cutting arrangement 30 described hereinbefore exhibits various drawbacks. Initially, it is necessary to exert a relatively high pressure on push-piece 32 in order to cut off the multiple zone sensor 28. Secondly, it is very difficult to gage manually the pressure exerted on the push-piece 32, given the heavy pressure necessary for cutting off the multiple sensor 28. Accordingly, the cut-off portion absorbs at the end of the cutting travel a high strain energy in a very short time lapse which generates a relaxation phenomenon propelling the cut-off portion relatively far from the case 22. This latter drawback represents a particular disadvantage given that the product to be analyzed risks spreading at least partially beyond the active zone in which it has been placed. Additionally, the localization of the cut-off portion can be rendered difficult given the indeterminate direction of propulsion of the cut-off portion. When the product to be analyzed is a product dangerous for man or his environment, this latter drawback renders utilization of the electrochemical measurement arrangement described hereinbefore hardly to be recommended.
A purpose of the present invention is to overcome the drawbacks mentioned hereinabove in providing a measurement arrangement including a cutting arrangement permitting a control of the advance of the blade in a manner to assure a slight displacement of the cut-off portion relative to the measurement arrangement.